This is Cloudina carinata which has been discovered in Spain and is an important fossil for understanding the evolution of skeletons. Unusually for such old fossils they have retained their three dimensional structure. They show evidence of asexual reproduction and are one of the oldest examples of reproduction in animals in the fossil record. It is still not known what Cloudina is and it has been compared to cnidarians and annelids.
Cloudinids are quite fascinating small shelly fossils. They are most often found near stromatolites, suggesting that they inhabited shallow waters and are never found in the same layers as the soft bodied Ediacaran fossils, even though there are deposits where they alternate, suggesting that they inhabited separate ecosystems. Seilacher suggested that they lived in microbial mats and that they built up their tubes in response to sedimentation, needing to grow in order to stay above. Their shells often show signs of predation and there are signs of budding, suggesting a colonial existence. They remain some of the most mysterious yet important fossils found.
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